Mechanical behaviours and mass transport properties of bone-mimicking scaffolds consisted of gyroid structures manufactured using selective laser melting

Bone scaffolds created in porous structures manufactured using selective laser melting (SLM) are widely used in tissue engineering, since the elastic moduli of the scaffolds are easily adjusted according to the moduli of the tissues, and the large surfaces the scaffolds provide are beneficial to cell growth. SLM-built gyroid structures composed of 316L stainless steel have demonstrated superior properties such as good corrosion resistance, strong biocompatibility, self-supported performance, and excellent mechanical properties. In this study, gyroid structures of different volume fraction were modelled and manufactured using SLM; the mechanical properties of the structures were then investigated under quasi-static compression loads. The elastic moduli and yield stresses of the structures were calculated from stress-strain diagrams, which were developed by conducting quasi-static compression tests. In order to estimate the discrepancies between the designed and as-produced gyroid structures, optical microscopy and micro-CT scanner were used to observe the structures’ micromorphology. Since good fluidness is conducive to the transport of nutrients, computational fluid dynamics (CFD) values were used to investigate the pressure and flow velocity of the channel of the three kinds of gyroid structures. The results show that the sizes of the as-produced structures were larger than their computer aided design (CAD) sizes, but the manufacturing errors are within a relatively stable range. The elastic moduli and yield stresses of the structures improved as their volume fractions increased. Gyroid structure can match the mechanical properties of human bone by changing the porosity of scaffold. The process of compression failure showed that 316L gyroid structures manufactured using SLM demonstrated high degrees of toughness. The results obtained from CFD simulation showed that gyroid structures have good fluidity, which has an accelerated effect on the fluid in the middle of the channel, and it is suitable for transport nutrients. Therefore, we could predict the scaffold's permeability by conducting CFD simulation to ensure an appropriate permeability before the scaffold being manufactured. SLM-built gyroid structures that composed of 316L stainless steel were suitable to be designed as bone scaffolds in terms of mechanical properties and mass-transport properties, and had significant promise

This figure displays the estimated functional coefficients by the MFG-LASSO from a hundred simulated data sets when <i>n</i> = 500, <i>σ</i> = 0.01.

The green curves are the true coefficient curves and the grey curves are the estimated coefficients. The estimated curves for the remaining of the coefficients from the seventh to the nineteenth are very similar to the fourth, fifth, and sixth functions (inactive coefficients) displayed in this figure.</p

The results of applying the proposed methods to the fMRI data when predicting the IQ and ADHD scores.

The results of applying the proposed methods to the fMRI data when predicting the IQ and ADHD scores.</p

Tuning Magnetic States of Planar Graphene/<i>h-</i>BN Monolayer Heterostructures via Interface Transition Metal-Vacancy Complexes

Planar graphene/h-BN (GPBN) heterostructures promise low-dimensional magnetic semiconductor materials of tunable bandgap. In the present study, interplay between 3d transition metal (TM) atoms and single vacancies (SVs) at the armchair interface in a planar GPBN monolayer was investigated through first principle density functional theory calculations. The TM-SV complexes were found to give rise to a rich set of magnetic states, originated from the interactions between valence electrons of the TM atom with dangling orbitals at the SV. The magnetic state at a TM-SV complex was further shown to be tunable upon the application of strain and electric field. The present study suggests a route to enrich and engineer the magnetic states of planar GPBN heterostructures, providing new insights for the design of tunable low-dimensional spintronic devices

Percentages of correct selection in the test set under various simulation scenarios when we have unbalanced time points for each observation.

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The regions of interests, the BOLD activities of which correlate the most with the ADHD score variability in a sample of subjects and achieve the lowest prediction error.

The regions associated with ADHD are colored red, those associated with ADHD Hyper/Impulsive are blue, and the ones associated with ADHD Inattentive are colored green.</p

The multi-slice display (Axial, Coronal, Sagittal) of the regions of interests, the BOLD activities of which achieves the lowest prediction error and correlate the most with the IQ score variability in the sample when the MFG-LASSO is used.

The regions associated with the IQ score are colored red, those associated with the performance IQ are blue, and the ones associated with the verbal IQ are colored green.</p

The multi-slice display (Axial, Coronal, Sagittal) of the regions of interests, the BOLD activities of which achieves the lowest prediction error and correlate the most with the ADHD score variability in the sample when the MFG-LASSO is used.

The regions associated with the ADHD score are colored red, those associated with the ADHD Hyper/Impulsive are blue, and the ones associated with the ADHD Inattentive score are colored green.</p

Supplementary materials.

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Average test RMSE of different methods under different simulation scenarios.

In each case, 100 random samples are used to compute the mean and standard deviation with parentheses.</p